A package is conventionally known which is installed with a heat sink as a package for use in relatively large heat generating semiconductor chip such as a graphics processor. Although a semiconductor device is known as is described in Japanese Laid Open Patent 2012-94592 for example as a package in which the upper surface of a heat sink is completely exposed, since warping is produced when the thermal expansion rate of the exposed heat sink and a sealing material is different, there is a problem with the adhesion strength between the heat sink and the sealing material and thus it is desirable that the heat sink be sealed within the package.